Heat exchange apparatus



May 14, 1957 1 VAN| 2,791,888

HEAT EXCHANGE APPARATUS Filed Sept. 22, 1955 3 Sheets-Shea?I 1 Infanzia?? Mame; Uzzz; "Slow l @vm gnou/da?,

May 14, 1957 J. VANI HEAT EXCHANGE APPARATUS Filed Sept. 22, 1955 5 Sheets-Sheet 2 JZZJQQW Jam@ Varzi y ad@ @Wm 1 Kuma@ 8 c/@zzorzeg J. VANI HEAT EXCHANGE APPARATUS May 14, 1957 3 shams-sheet s Filed Sept. 22, 1.955

HEAT EXCHANGE APPARATUS `lames Vani, Midlothian, Ill., assignor to Controlled Heat Transfer Corporation, Chicago, lll., a corporation of Illinois Application September 22, 1955, SeriaiNo. 535,964

3 Claims. (Cl. 62-91.5)

This invention relates to heat exchange apparatus, and more particularly to refrigeration apparatus wherein the rate of heat exchange with the air in a storage space is controlled in a manner to maintain that space at a predetermined temperature.

Space refrigerating apparatus hertofore developed and utilized has had as its primary object that of removing eat from the air in the space, in order to cool it and any other contents, usually food products, located in the space to a desired temperature. The concept of refrigeration involved was to bring the air in direct contact with a heat exchanger such as a conduit or coil through which was circulated a refrigeration liquid cooled to a suitably low temperature. This produced the result ofrapid cooling of that air and rapid warming of the refrigeration liquid circulating through the heat exchanger, This result in turn caused the air surrounding the lower portion of the coil to be cooled to a much greater extent than the air surrounding the upper portion of the coil. Further, this brought the temperature of the air contactingthe heat exchanger to the temperature of the circulating refrigeration liquid, and thus resulted in overcooling of the space surrounding the lower portion of the coil. This precluded the use of refrigeration liquids circulating at temperatures considerably lower than the desired temperature.

Certain prior refrigeration apparatusincorporated a secondary refrigeration system circulating a liquid which had heat exchange relation with a basic, liquid circulating refrigeration system. Such an apparatus was commonly attended by leakage of liquid, generally required heavy and cumbersome equipment for the secondary system, and was poorly suited to application where a small installation Was required.

An object of this invention is to provide new and improved refrigeration apparatus for maintaining a storage space at a predetermined temperature. v

Another object is to provide refrigeration apparatus including a novel heat exchange panel capable of utiliz ing therein a refrigeration liquid circulated at a relatively low temperature without overcooling the storage space in which the panel is located.

Another object is to provide refrigeration apparatus including a novel heat exchange panel incorporating a heat exchange retarder designed and constructed so as to resist uctuations in temperature and to maintain a substantially constant temperature in the storage space in which located, by retarding and modulating the transfer of heat units from that space to the refrigeration liquid.

Yet another object is to provide refrigeration apparatus including a novel heat exchange panel incorporating a heat exchange retarder operative to resist the exchange of heat units near the entry-point into the heat exchange panel of cold refrigeration liquid, having the dualy effect of spreading the area through which heat transfer takes place over a larger portion of the panel, and of minirnizing the temperature variance throughout the dimensions of that panel. i

nited States Patent 'i Patented May 14, 1957 ice A further object is to provide refrigeration apparatus including a novel heat exchange panel so provided with interior passages and so positioned in the space to he kept cool as to direct the refrigeration liquid circulating through those passages into more effective contact with the passage walls, for more effective transfer of heat through those walls.

A further object is to provide new and improved refrigeration apparatus for maintaining a predetermined temperature in a storage space, the apparatus including a novel heat exchange panel whereof the heat exchange retarder is formed of a cellular material within which air is entrapped.

I A further object is to provide refrigeration apparatus for maintaining a predetermined temperature in a storage space, the apparatus including a heat exchange panel provided with a novel heat exchange retarder capable of. acting as a reservoir to absorb heat units when the air in the storage space is warmed, to prevent the immediate reaction by the refrigeration apparatus to this increased temperature by supplying additional refrigeration liquid to the heat exchange panel.

A still further object is to provide new and improved refrigeration apparatus which can be easily and inexpensively installed in trucks, truck trailers, refrigerator cars, ships, stationary refrigeration rooms, storage rooms and the like.

Yet a further object is to provide refrigeration apparatus employing a novel heat exchange panel'provided with a heat exchange retarder, in combination with a Simple andnon-mechanical primary heat absorber, such as solidified carbon dioxide, in such a manner as to cause but gentle changes in temperature in the space to be kept cool.

Other objects and advantages of this invention will become apparent from the `detailed description hereinafter set forth taken in connection with the appended drawings in which:

Figure l is an elevational View, with portions broken away and in section, of one embodiment of my apparatus adapted to application as a refrigeration system in a truck-trailer;

Fig. 2 is an enlarged fragmentary vertical sectional view of a portion of the structure of Fig. l;

Fig. 3 is a fragmentary transverse sectional view taken along line 3 3 of Fig. 2;

Fig. 4 is an enlarged fragmentary, elevational view of one of the heat exchange panel assemblies, with a portion broken away and in section;

Fig. 5 is an enlarged transverse sectional view taken along line 5--5 of Fig. 4;

Fig. 6 is an enlarged fragmentary sectional view taken along line 6 6 of Fig. 5, with the additional showing of means installed to protect said panel assembly;

Fig. 7 is a fragmentary transverse sectional view taken along line '7 7 of Fig. 2;

Fig. 8 is a fragmentary sectional view taken along line 8-8 of Fig. 7; and

Fig. 9 is a side elevational view with parts broken away and in section showing the panels and protecting means therefor.

I have illustrated herein my refrigeration apparatus installed in a truck-trailer, although such is only one of the many possible embodiments thereof hereinafter mentioned.

The refrigeration apparatus in accordance with a preferred embodiment illustrated herein comprises primary heat absorbing means 10, and ultimate heat exchangers 11 disposed in a rectangular, box-like space to be cooled. This space is defined by insulated Walls 12, an insulated roof 13, and an insulated oor 14. The apparatus also comprises means for circulating a refrigeration liquid 1 5 in heat exchange relation with the primary heat absorbing means, including cold side conduit means 16 carrying the liquid from contact with the primary heat absorbing means to the ultimate heat exchangers, and warm side conduit means 17 returning the liquid from the ultimate heat exchangers to the primary heat absorbing means.

The space to be cooled herein referred to, comprises that space contained with a completely insulated enclosure wherein the temperature of the air and any other contents is to be maintained at a predetermined level. It is intended that once the air contained therein be cooled to a denite predetermined temperature, no further lowering of the temperature will occur, but that the air will be merely maintained at the predetermined temperature. Preferably the material to be stored within the insulated enclosure will be pre-cooled to the desired temperature prior to its introduction into the space to be cooled. It will, of course, be apparent that it will be necessary to maintain circulation of the refrigeration liquid to the space as the air therein tends to become warm owing to the passage of heat into the space through the insulated walls. A further warming elect will be occasioned by the opening of the door or doors into the space for introduction or removal of stored material, as well as occasioned by the introduction of materials not precooled, as preferred.

The primary heat absorbing means comprise a container or bunker 18 adapted to receive and contain blocks 60 or cartons of a solid refrigerating medium, preferably solidified carbon dioxide, which is commonly called dry ice, and arranged for circulation of a refrigeration liquid in heat exchange relation to the Dry Ice. The use of Dry Ice as a heat absorber substance is desirable because of its known properties including its high heat absorbing capacity and lack of liquid or solid residue. The bunker 18 is of generally rectangular, box-like shape and has outer walls formed by an outer box-like element 19 and an inner box-like element 20, with a suitable insluation 21 interposed between the outer and inner elements, which elements are formed preferably of sheet material such as aluminum. A container 25 defining a chamber for receiving the Dry Ice is disposed within the bunker outer walls, and is spaced therefrom to define therewith a reservoir 23 for the refrigeration liquid. The container comprises a lloor formed into three sections 32, 33 and 34, and three walls 24, the fourth wall portion being that presented by one wall portion 20a of the inner element. The container floor is spaced from the floor portion 20b of the inner element, and is of less Varea than the uppermost cross section of the container. The three container Walls incline slightly outwardly, and the entire container is joined to the bunker by sealing the edges 26 of the Walls and floor of the container to the inner element. The spaces between the inclined container Walls and the walls of the inner element, together with the space between the sectional floor of the container and the oor of the inner element, define the reservoir, which has a generally scoop-like shape. v

The container oor is shaped into sections 32, 33 and 34, the two outer sections 32 and 34 being formed as to be perpendicular to the adjoining inclined container walls. These sections themselves, therefore, incline at moderate angles from the horizontal. These inclined floor sections cause the solidified carbon dioxide to bear constantly not only against the reservoir oor, but also against the container Walls. The perpendicular relationship between oor and wall causes a more complete engagement thereof by the rectangular Dry Ice blocks, for a more effective absorption of heat from the refrigeration liquid.

The container walls and oor sections are preferably fashioned of sheet material, such as aluminum, having desirable heat transfer characteristics, since it is through this material that a transfer of heat is effected to remove heat from the liquid being circulated through the apparatus.

An expansion header 27 joins the free corners 28 and 29 of the reservoir 23 and is connected into both branches of the reservoir to provide not only a space into which the liquid may expand, but also a circulation channel across the top of the reservoir. A filler pipe 30 extends into the header 27 for addition of any necessary liquid, and is provided with a suitable closure cap. A vent 31 is provided for escape from the bunker of the gas generated or released by the solidified carbon dioxide.

The bunker preferably is disposed substantially within the space to be cooled and in the uppermost portion thereof for reasons hereinafter set forth, but is provided with a door 22 permitting access to the interior of the container. This door preferably is opened to the outside of the insulated walls of the space to be cooled so that it is not necessary to open or enter the insulated space in order to charge the bunker with Dry Ice as hereinafter explained A plurality of ultimate heat exchangers 11, preferably identical in construction, are located within the space to be cooled, and each takes the form of a substantially llat panel assembly. Each panel assembly comprises a heat exchange panel 35 fashioned of a metal having desirable heat transfer characteristics, as for example aluminum, a heat exchange retarder 41, and an external casing 44. Each panel is formed from two complementary shaped, relatively thin sheets 43 of metal bonded together at predetermined areas and not bonded at other predetermined areas. The non-bonded areas of this panel are expanded or separated to form a plurality of internal longitudinal passages 36 for the refrigeration liquid, all passages connected at their upper and lower ends to two header passages 36a, respectively. When so constructed, the longitudinal passages are separated one from the other by the bonded areas 37, and the entire panel is surrounded by bonded peripheral flanges 38. The header passages open at one end respectively into an entry connection 39 for the cold side conduit means 16, and into an exit connection 40 for the warm side conduit means 17.

In order to provide for substantial uniformity of temperature between the upper and lower portions of the panel 35, a heat exchange retarder 41 is disposed around each panel in enveloping relation, except at the peripheral portions thereof. This retarder preferably comprises a cellular material laid about both sides of the panel, and which for convenience takes the form of two sheets of material disposed respectively against opposed faces of the panel. A cellular or foam rubber or cellular or foam plastic sheeting is suitable for this purpose, desirably containing dead air entrapped within its cells.

The thickness of the retarder material may vary considerably in various applications depending upon the conditions to be met. However, excellent results have been obtained by using a cellular or foam rubber or plastic sheeting approximately one-half inch in thickness in apparatus employing a refrigeration liquid cooled by solidied carbon dioxide.

The heat exchange retarder separates the air in the space to be cooled from direct contact with the panel, which latter has a temperature equivalent to the low ternperature of the liquid. This retarder further serves to slow the absorption by the panel of heat from the space to be cooled with the result that the entire panel and entire heat retarder reach and maintain a substantially uniform temperature throughout their dimensions. Due to the properties of the heat exchange retarder, the temperature of the refrigeration liquid when it leaves the panel assembly through the exit connection 40 is not much greater than the temperature of the liquid when it enters the assembly through the entry connection 39. For these reasons, the temperature of the space to be cooled adjacent the lower portion of the panel assembly is not much lower than the temperature of the space adjacent the upper portion of the panel assembly. Therefore the ternperature of the space to be cooled does not vary substanannees tially from bottom to top. It should be noted atithis point that the panel assemblies are preferably of such length that they extend throughout a substantial portion of the vertical height of the space to be cooled so as to maintain a substantially uniform temperature throughout nearly the entire vertical extent of such space. It should also be noted that a suicient number of panel assemblies preferably are employed, and so arranged as to extend horizontally substantially throughout the length of such space. Maintenance of a substantially uniform temperature at all portions of the space is thereby provided for. To this end the panel assemblies are distributed along the two principal (longitudinal) side walls of the space to be cooled as shown in the illustrated embodiment. The space preferably is limited in its lateral dimension so as to avoid having a space between opposing panel assemblies so great as to cause an excessive variation in temperature between the air space adjacent the walls of the space where the panel assemblies are located and the air space intermediate the two banks of panel assemblies.

In the illustrated embodiment using Dry Ice as the primary heat absorber it was found that the difference in temperature between the liquid entering the panel assembly and the liquid leaving the panel assembly was not more than approximately 6 to 7 (Fahrenheit scale). lt will be understood that the temperature of the liquid entering the panel assembly is only slightly higher than the temperature of the Dry Ice.

A casing 44;, in turn, surrounds and encloses the panel and the enveloping heat exchange retarder, retaining the retarder about the panel, and protecting both the panel and the retarder from damage. This casing is formed of two identical sheets of metal 61 and 62, each sheet of dimensions slightly exceeding the planar dimensions of the panel. Each casing sheet is dished shallowly to accommodate one side of the retarder-covered expanded passage-defining portions of the panel, and each Sheet is provided with a flanged rim 63 extending around its lateral edges. When these casing sheets are positioned to envelop the panel and retarder, the casing rims sandwich the panel flange 33. However, two adjacent rim sides of each casing sheet extend beyond the panel flange to allow completion of the assembly by folding each extending rim over the panel flange and the opposing casing rim adjacent the panel ange to form laps 45.

The metal sheets 61 and 62 forming the casing 44 are of sufficient strength to not only protect the panel but to provide sufficient strength and impart sufficient rigidity to the panel assembly to insure its retention of shape and rigidity during use. To this end preferably the sheets are formed of metal of 1/16 inch thickness. These sheets 61 and 62 preferably are formed from aluminum which is anodized to impart a black color thereto. It is to be noted that dark surfaces are more effective heat absorbers. The panel assemblies may be made in any size throughout a substantial range of sizes, but in any particular installation, all panel assemblies preferably are of the same dimensions and are similar in all respects. Excellent results have been obtained in a system such as shown herein with the panel assemblies having dimensions of approximately fifteen inches in width, sixty inches in length and two inches in external thickness.

The panel assemblies 35 are disposed in the space to be cooled with the panel faces generally in vertical planes, and preferably parallel and close to the walls of that space.

Each panel is positioned with its longitudinal medial axis inclined at a slight angle with the vertical. In the illustrated embodiment the panel assemblies are disposed at an angle of approximately with the vertical, although this angle is not critical. It is important, however, that this angle be sufficiently large to cause the ow of liquid to be directed against the inner surfaces of the passages 36 when the liquid is reacting to convec- `tion forces caused by changes in density in that liquid.

It has been found that by so positioning the panels, and therefore their longitudinal passages, at an angle with the vertical, a more eicient and better heat exchange is realized through the walls of those passages. It is believed that this beneficial result is occasioned because the streamline flow of liquid is prevented. Such ow is considered to be attended by the formation of an insulating film of liquid on the inner surfaces of the passages. This film interferes with the efiicient transfer of heat along the passage walls. When these passages are disposed on an incline, however, convection forces cause the liquid to tend to flow in a vertical direction within the inclined longitudinal passages. In other words, the convection forces impart a vertical velocity component to the liquid, with the result that the liquid is caused to impinge against the uppermost portions of the passage walls, scouring off any insulating film. Such a scouring action permits the liquid to maintain an effective contact with the heat transferring walls of those passages.

Each panel assembly is mounted along Ithe walls of the space to be cooled in substantially vertical position by any suitable means, such as channels 48 disposed longitudinally along the principal walls of the space to be cooled. Bolts 46, penetrate through the laps 45 and flanges 38 to afiix the panels to the channels.

The panel assemblies are spaced apart and are spaced from the side walls of Ithe space to be cooled in order to permit free circulation of the air in such space past the spaces of the panel assembly. This creates a slight convection effect in the air in the space to be cooled which further aids in creating a uniform temperature throughout the space to be cooled. Moreover, the exposure of both faces of each panel assembly to the space to be cooled greatly increases the cooling effect produced.

In addition to the protection afforded by the casing, protection from rough treatment such as might occur in the handling of crates, cartons and the like during loading or unloading of the space, is provided by wooden rails 49 mounted on spacers 5t) axed to the same channels 48 as the panels. Mounting the panel assemblies onto the channels on the walls of the space to be cooled, and protecting them with the wooden rails, provides adequate air circulation space about all sides of the assemblies. The resultant more efficient air circulation about the panel assemblies is instrumental in creating a more uniform temperature in that space.

The illustrated embodiment includes a multiple panel installation with a plurality of identical panel asemblies adjoining one another to present la plane of panel surfaces. In the present embodiment, banks of panel assemblies are shown along the opposing principal walls of the space to be cooled.

Having provided retarders for preventing stratification of air of differing temperatures within the space to be cooled, substantial uniformity in temperature throughout the longitudinal extent of that space is accomplished by maintaining all panels at substantially one temperature. This can best be accomplished by supplying each panel with refrigeration liquid of substantially the same temperature. To this end, cold side conduit means 16 are provided in a manner comprising a single cold pipe 5l for each panei bearing wall of the space to be cooled, a single manifold header S2 in that cold pipe, two cold side manifolds 53 connected directly to the header, and a plurality of entry conduits 54, one for each panel, connecting each panel by its entry connection to its respective manifold. The single cold pipe leads downwardly from the reservoir, which is in heat exchange relation with the Dry Ice, and connects into the single manifold header which is located adjacent the entry connections of the panels of that wall. The two manifolds S3 extend longitudinally along the base of each panel-bearing wall of the space to be cooled. One entry conduit for each panel interconnects a manifold to the entry connection of each panel of the group supplied by that manifold.

Use of the single cold pipe and single header substantially eliminates the need for duplication of conduits leading from the reservoir to the manifolds, thus saving that expense, and the necessity and expense of insulating the duplicating lengths of conduits. Each panel bearing wall is provided with the 'two manifolds, each supplying refrigeration liquid to a group of panels adjacent that wall. That is to say, the panel assemblies along each panel bearing wall of the space to be cooled are connected in two groups, all panels of a group being connected in parallel through the manifold for that group, and the two groups themselves connected in parallel through the manifold header.

In one practical application of this conduit means, it has proved possible to maintain a large lbank of panels all at substantially the same temperature, by utilizing a manifold header and group manifolds and thereby circulating liquid of the same temperature to successive groups of panels, as well as circulating liquid of the same temperature to successive panels in each group.

After circulating from the entry connection through the longitudinal extent of each panel, the liquid is deemed warm relative to its desired temperature, and provision is made for its return to the reservoir through lthe warm side conduit means 17. These means comprise an exit conduit 57 for each panel, and joining the exit connection thereof to the warm manifold 58 for that group of panels. A warm conduit 59 connects each Warm manifold to the reservoir in a manner to discharge the relatively warm liquid into the uppermost portion of the reservoir.

The temperature of the space to be cooled is maintained at the desired value by controlling the rate of circulation of the refrigeration liquid. This is accomplished by providing valve means in each of the several warm conduits 59 returning the liquid to the reservoir. Each valve means is thcrmostatically controlled in relation with the temperature in the space to be cooled. Accordingly, I provide in each warm conduit 59 a valve 64 which is controlled by a `thermostat 65, which in the illustrated embodiment is located close to the valve, but exteriorly thereof and in the space to be cooled. It should be undersood however that the thermostat 65 may be located at any other suitable point within the space to be cooled and suitably connected to the valve by known means for actuating the valve. A proper setting of the thermostats to maintain a desired temperature in the space to be cooled, will cause the thermostat to actuate its dependent valve to control the rate of flow of refrigeration liquid.

A suitable shut-o valve 56 and suitable drain or bleeder valve 55 are provided in each cold pipe.

it will be seen that a closed circuit is completed by the aforementioned reservoir, cold side conduit means, panels and warm side conduit means. Convection cycling of the refrigeration liquid ythrough this circuit is brought about by locating the bunker 18, and therefore the reservoir 23, in the uppermost portion of the space to be cooled, and relatively higher than the panels. The cold liquid leaves the reservoir by convection flow induced by its increased density, passing downwardly through the cold pipe, longitudinally through the header and cold manifolds, and through the entry conduits to the panels. Convection pressure caused by succeeding cold liquid and caused by the liquid being warmed as it passes through the panel, forces the liquid up through the length of the panel. As the liquid is warmed in the panel, it further adds to the convection cycling by its decrease in density.

In the use of the apparatus in accordance with the preferred embodiment of my invention herein illustrated, Dry Ice either in block-form or in bulk form contained in cartons is disposed in the bunker 18, and the bunker door 22 ciosed. As hereinbefore described, `the Dry Ice bears against both the floor sections 32, 33 and 34, and the walls Z4 Vof the container, `whereas the refrigeration liquid is in contact with the opposite sides of the same walls and floor. This liquid is cooled due to its heat exchange relation with such Dry Ice, and passes downwardly along the side walls and into the lower portion of the reservoir. The cooled refrigeration liquid leaves the reservoir 23 through the cold pipe 51 through which the liquid passes to the manifold header 52. The liquid takes diverging paths in the header to enter the two manifolds 53 which connect directly into the header. It then flows through these manifolds to pass into the several entry conduits 54 connecting the manifolds to the several panels by means of the entry connections 39. The refrigeration liquid in the passages 36 of the panels absorbs heat from the air in the space to be cooled and thereby is warmed, whereupon it rises due to the convection effect caused by its changed density. After rising through the extent of the panel, the liquid leaves each panel through the exit connection 46, and returns through the exit conduits 57 to the warm manifolds 58 from whence it is returned to the reservoir through warm conduits 59, and discharged into the upper portion of the reservoir for re-cooling.

All conduits, manifolds, manifold headers, valves and controls are suitably insulated, even though not illustrated in the drawings.

Although the illustrated embodiment relates to refrigeration apparatus utilizing a non-chemical primary heat absorbing means, any means of heat absorption may be utilized in my invention; similarly it is contemplated that mechanical, forced How means may be employed to augment the convection flow for those certain installations in which convection flow is insuicient. In like manner, it is within the scope of my invention to connect my novel panels into a system in other fashions, as by connecting them through a manifold directly to the reservoir without rst manifolding them into groups, by connecting each panel directly to the reservoir, or by adding to the number of groups of panels on each wall.

Referring again to the description of my invention as refrigeration apparatus in a truck-trailer, it is also contemplated that my heat exchange apparatus as illustrated in Figs. l through 9, with modifications, may be employed equally well in other refrigeration applications such as non-mobile refrigeration storage spaces and compartments, ships, railroad cars and other applications where the primary object is the maintaining of a constant predetermined temperature.

It Will be seen that the foregoing description of my refrigeration apparatus relates to such an apparatus capable of effectively maintaining uniformity of temperature of the air within a space to be cooled, such uniformity being maintained not only dimensionally throughout the vertical and lateral extents of that space, but also timewise, inasmuch as the apparatus effectively maintains that uniform temperature for prolonged periods of time. This uniformity of temperature is accomplished by the use of an extremely cold refrigeration liquid and thereby is accomplished with a high degree of heat exchange efficiency achieved in a relatively small system. The use of this extremely cold refrigeration liquid further serves to permit an accurate and sensitive control of the temperature in the cooled space.

The capability of my refrigeration apparatus of using Dry Ice, or a substance of similar characteristics, as the basic heat absorber, eliminates the possibility of mechanical failure in the primary cooling means, and eliminates the inconvenience that attends a system requiring cleaning and drainage of that means. Such a capability further allows the use of an extremely simple bunker construction, adding to the reduction of complexity of my apparatus. Since the Dry Ice has such eicient heat absorbing characteristics, consumption of the basic heat absorber in my refrigeration apparatus is relatively slow. This slow consumption is advantageous in that recharging of the bunker with additional or replacement Dry Ice need be'accomplished but infrequently.

aromas An additional advantage is derived from my refrigeration apparatus from its utilization of convection forces to circulate the refrigeration liquid. The simple circuit required means that the apparatus will necessarily be less expensive to build, and that the possibility of mechanical failure in the circulating means will be absent. lt will further be seen that the circulation circuit will require substantially no maintenance or servicing.

Added to all the aforementioned advantages of my refrigeration apparatus, it can be seen that my apparatus can be readily built in an indefinite variety of sizes and modifications, and that it can be readily and easly installed in any of a series of limited spaces such as might be found in existing trucks, truck-trailers, ships, storage rooms and refrigerator cars requiring the maintaining of a predetermined temperature therein, all such installations being possible with a minimum of structural modification of those items themselves. The installed apparatus will provide a light-weight, relatively-inexpensive installation so compact as to encroach on a minimum of the space to be cooled.

While I have herein shown a preferred embodiment of the invention, it is understood that certain changes may be made in my illustrated embodiment without departing from the scope of the appended claims.

I claim:

l. Refrigeration apparatus comprising an ultimate heat exchange panel having a plurality of internal longitudinal passages for refrigeration liquid, said longitudinal passages connecting at the ends thereof into a single entry header and into a single exit header respectively, an entry connection and an exit connection for said entry and exit headers respectively, said panel being positioned within a space to be cooled with said longitudinal passages disposed at an angle with the vertical and with said entry connection relatively lower than said exit connection, a heat exchange retarder formed of cellular material enveloping said panel, basic heat absorbing means, said means comprising an enclosed insulated bunker, a container for solidified carbon dioxide within said bunker, a reservoir for refrigeration liquid substantially surrounding said container and formed between the floor and walls of said container and the insulated floor and walls of said bunker, solidified carbon dioxide in said container, and an access door into said container through one wall of said insulated bunker, said bunker being positioned relatively higher than said panel, conduit means interconnecting the lower portion of said reservoir and said entry connection, conduit means interconnecting said exit connection and the upper portion of said reservoir, said ultimate heat exchange panel, said conduit means and said reservoir comprising a closed circuit, and refrigeration liquid in said closed circuit, said refrigeration liquid in said reservoir being in heat exchange relation with said solidified carbon dioxide.

2. Refrigeration apparatus comprising a plurality of substantially flat panel assemblies, each panel assembly having two opposite principal faces, and each said panel assembly comprising a heat exchange panel having a plurality of internal longitudinal passages for refrigeration liquid, said passages connecting at the ends thereof into a single entry header and a single exit header respectively, and an entry connection and an exit connection for said entry and exit headers respectively, each said panel assembly being positioned within a space to be cooled with said panel assembly faces in vertical planes, each said panel assembly being further positioned with said longitudinal passages disposed as to incline from a vertical line and with said entry connection relatively lower than said exit connection, a heat exchange retarder formed of cellular material enveloping each panel, and a casing surrounding said retarder-enveloped panel and retaining said retarder against said panel, basic heat absorbing means, said means comprising an enclosed insulated bunker, a container for solidified carbon 'dioxide within said bunker, a reservoir for refrigeration liquid substantially surrounding said container and formed between the floors and walls of said container and the insulated floor and walls of said bunker, solidified carbon dioxide in said container, and an access door into said container through one wall of said bunker, said bunker being positioned relatively higher than said panels, cold side conduit means forming an in-parallel interconnection between said reservoir and said panels, said means comprising a single cold side manifold, a cold pipe interconnecting the lower portion of said reservoir and said cold side manifold, and an entry conduit for each panel, each of said entry conduits interconnecting one said entry connection respectively and said cold side manifold, warm side conduit means interconnecting all exit connections and said reservoir, said means comprising a warm side manifold, an exit conduit for each panel, each of said exit conduits interconnecting one said exit connection respectively and said warm side manifold, and a warm conduit interconnecting said warm side manifold and the upper portion of said reservoir, said ultimate heat exchange panels, said warm side conduit means, said reservoir and said cold side conduit means comprising a closed circuit, and refrigeration liquid in said closed circuit, said refrigeration liquid in said reservoir being in heat exchange relation with said solidified carbon dioxide.

3. Refrigeration apparatus comprising a plurality of substantially fiat panel assemblies, each panel assembly having two opposite principal faces, and each said panel assembly comprising a heat exchange panel having a plurality of internal longitudinal passages for refrigeration liquid, said passages connecting at the ends thereof into `a single entry header and a single exit header respectively, and an entry connection and an exit connection for said entry and exit headers respectively, each said panel assembly being positioned within a space to be cooled with said panel assembly faces in vertical planes, each said panel assembly being further positioned with said longitudinal passages disposed as to incline from a vertical line and with said entry connection relatively lower than said exit connection, a heat exchange retarder formed of cellular material enveloping each panel, and a casing surrounding said retarder-enveloped panel and retaining said retarder against said panel, basic heat absorbing means, said means comprising an enclosed insulated bunker, a container for solidified carbon dioxide within said bunker, a reservoir for refrigeration liquid substantially surrounding said container and formed between the floors and walls of said container and the insulated floor and walls of said bunker, solidified carbon dioxide in said container, and an access door into said container through one Wall of said bunker, said bunker being positioned relatively higher than said panels, cold side conduit means interconnecting said panels into a plurality of groups and interconnecting said groups and said reservoir, said panels in each group being n an in-parallel interconnection with the other panels within said group, each said group of panels being in an in-parallel interconnection with the `others of said groups, said cold side conduit means comprising a manifold header, a cold pipe interconnecting said header and the lower portion of said reservoir, a plurality of cold side manifolds in number equal to the number `of groups of panels, and an entry conduit for each panel, the entry connections of all panels of each group being interconnected with the cold side manifold for said group by the entry conduits of each said panel respectively, and all said cold side manifolds being interconnected with said header, warm side conduit means interconnecting all exit connections and said reservoir, said means comprising a warm side manifold for each group of panels, an exit conduit for each panel of each said group, said exit conduits for each panel of each group interconnecting the exit connection and said warm side manifold for said group, and warm conduits interconnecting each warm side manifold and the upper portion of said reservoir,

References Cited inthe le of this patent UNTED STATES PATENTS Copeman Nov. l5, 1932 Cowan Oct. 30, 1934 Bohemier et al Feb. 19, 1935 Elsey Oct. 13, 1942 Keller Apr. 20, 1948 Morrison Jan. 6, 1953 

